Monday, 28 November 2011

Neptune

Neptune meansAt first, Neptune was only the god of water, but later on this was extended to include the sea when he became associated with the Greek god Poseidon.

The PlanetFor many, centuries people did not know that this planet even existed. It was discovered by Johann Galle and Heinrich D'Arrest in 1846. Neptune is the smallest of the four gas giants in our Solar System. Much like Saturn and Uranus, Neptune's atmosphere contains hydrogen, helium and methane.

Not much was known about Neptune until it was visited by the spacecraft Voyager 2 on August 25, 1989. Voyager 2 took many pictures of the planet, and much of what we know today about Neptune came from this single visit. These pictures show a brilliant blue planet with a few thin white clouds laced around its surface.

In Neptune's atmosphere, there is a large white cloud that moves around rather quickly. The "scooting" of this cloud around the atmosphere has led it to be named "Scooter." When Voyager 2 visited Neptune, its pictures showed a giant storm much like the storm on Jupiter. This storm is called the "Great Dark Spot" because it appears as a dark oval shape on the surface of the planet. We do not know how long this storm has been active or if it is still present. More recently, the Hubble Space Telescope sent pictures back to Earth and there was no sign of the Great Dark Spot. These pictures did show two other dark spots that eventually faded away.

Neptune is a very windy place. No other planet in the Solar System has winds that are as strong as Neptune's. The winds near the Great Dark Spot were believed to have reached nearly 1,200 miles per hour (approx 1931 km per hour). Perhaps this extremely windy atmosphere contributes to the appearance and disappearance of the great dark spots.